Glock 40 S&W Barrel Conversions

9mm, 357 Sig, and 40 S&W

Having the diversity of calibers and barrel configurations for the AR-15 rifle makes it an excellent rifle that can be employed to take a variety of creatures. Similarly, some Glock pistols support different calibers, too. Glocks chambered in .40 S&W can reliably shoot both .357 Sig and 9mm ammunition. It's a great day when you have a gun that can shoot more than one caliber.



The .357 Sig is another high pressure round like the .40 S&W. You can think of the .357 Sig as a necked down .40 much like the .243 Remington is a neck down version of the .308 Winchester. The bases of the cartridges are the same, therefore, no new Glock slides are necessary. Furthermore, Glock pistols are rated for +P ammunition allowing it to handle to greater .357 Sig chamber pressures. For example, to convert a Glock 22 to .357 Sig, one need only purchase an OEM Glock .357 Sig barrel and swap the two. Barrels can be purchased from places online like Lone Wolf Distributing and RockYourGlock. You don't even have to buy different magazines as the original will feed the .357 Sig ammo.

Glock 22 with .357 Sig drop-in barrel

You can even shoot quality 9mm rounds out of a Glock once chambered for .40 S&W. From Lone Wolf Distributing, you can also pick up an aftermarket 40 to 9 conversion that is also a drop in replacement barrel.  Lone Wolf does recommend shooting good 9mm ammo to ensure reliability. I've had no problems shooting 115 grain ball ammo through my Glock 27 converted to 9mm.

Glock 27 with LWD 40-9 barrel

The conversion to 9mm from 40 S&W does require the shooter to use 9mm magazines because of the smaller cartridges. For my Glock 27, I use G26 magasines when shooting 9mm ammunition.

Having the diversity to shoot different calibers makes the Glock pistol a great gun like the AR-15. Or, you could just buy a bunch of Glocks in whatever caliber they offer...Oh wait, I already have a butt-ton of Glocks.